Low-frequency treatment device



FIG. 1 is a perspective view of a low-frequency treatment device showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof;

FIG. 8 is a bottom perspective view thereof; and,

FIG. 9 is a perspective view of using status thereof.

The broken lines illustrate portions of the low-frequency treatment device that form no part of the claimed design. 

CLAIM The ornamental design for a low-frequency treatment device, as shown and described. 